1. Field of the Invention
The present invention relates to a pipe assembly unit with built-in flow sensors in which a main pipe and branch pipes are integrated.
2. Description of the Related Art
There has hitherto been known a piping construction in which a pipe assembly is formed by connecting a main pipe and branch pipes of multiple systems and a flow sensor is mounted to each of the multiple branch pipes, whereby the monitoring of flow rates is performed. In the case of a piping construction of this kind, it is necessary to perform the connection of the main pipe and the branch pipes and the connection of the branch pipes and the flow sensors for each number of the systems of the branch pipes. At present, therefore, workers are forced to perform troublesome piping work.
In connecting these pipes, seal tape is wound around a nipple in order to prevent liquid leakage from a connection and sealing is performed by screwing the nipple with tape into the connection. In the case of this method, the seal tape is crushed when the nipple is screwed in, with the result that the sealing properties are improved. On the other hand, because the nipple becomes buried as it becomes screwed in and the height of the nipple decreases, it is difficult to adjust the length of the whole piping. Besides, the orientation of connected pipes must be coordinated at the same time with the length adjustment, and positioning with respect to the assembling direction in the connection is difficult. Thus, very troublesome execution of work has hitherto been required. In addition, the number of parts increases because nipples and seal tape are used in all connections, posing the problem that equipment expenses are high. Incidentally, it is also conceivable to adopt a method in which sealing is performed by applying a liquid gasket to the circumference of a nipple. However, problems similar to those occurring in connection with seal tape still arise even when this method is used.
Against the background of the above circumstances, techniques for making piping work efficient have also been proposed (refer to Japanese Patent Laid-Open No. 11-173884, for example). In the technique disclosed in Japanese Patent Laid-Open No. 11-173884, flow detectors with built-in flow regulating valves are mounted on multiple manifold blocks and the flow detectors are connected by screws, whereby a pipe assembly of multiple systems can be formed. Even in this technique, however, troublesome work for fastening the screws to multiple mounting seats on the manifold blocks cannot be avoided when multiple pipes connect to the flow detectors, and it cannot be said that the burden on workers is completely eliminated. Also, because the mounting posture of the manifold blocks is determined beforehand and the orientation of pipes cannot be made variable, the degree of freedom in the arrangement of piping is low and there is still room for improvement in this respect.
The present invention has been made in view of the above circumstances and has as its object the provision of a pipe assembly unit with built-in flow sensors which enables piping work to be performed with good efficiency, reduces cost by a reduction in the number of parts, and makes mounting positions variable, whereby the degree of freedom in the arrangement of piping can be raised.